v10.39 - Released RULES diagram infrastructure doctrine

Summary

• make diagram/ required governed-docs infrastructure for RULES
• require diagram/STRUCTURE.md as the compact active whole-project diagram-side entrypoint
• preserve design/** as semantic authority and future diagram/history/ / diagram/done/ as preservation infrastructure

Verification

• runtime install/update verification passed for the touched active runtime owners
• source/runtime parity and body-sufficiency checks passed in checked scope
• git diff --check passed
• source docs/design/changelog/TODO/phase/patch surfaces were synced for the release